[Tex/LaTex] how could we create this tree diagram

Question

How could we create the following tree diagram in a seperate page which has horizontal landscape?

Answer 1

A rough answer based on forest:

\documentclass{standalone}

\usepackage{forest}

\begin{document}

\forestset{
  L1/.style={fill=green,},
  L2/.style={fill=orange,edge={orange,line width=2pt}},
  L3/.style={fill=yellow,edge={yellow,line width=2pt}},
  L4/.style={fill=pink,edge={pink,line width=2pt}},
}

\begin{forest}
    for tree={
        grow=0,reversed, % tree direction
        parent anchor=east,child anchor=west, % edge anchors
        edge={line cap=round},outer sep=+1pt, % edge/node connection
        rounded corners,minimum width=15mm,minimum height=8mm, % node shape
        l sep=10mm % level distance
    }
  [AAAA,L1
    [EEEE,L2
        [EEEE,L3
            [YYYY,L4][AAAA,L4]
        ]
        [DDDD,L3
            [DDDD,L4][KKKK,L4]
        ]
        [PPPP,L3
            [KKKK,L4][KKKK,L4]
        ] 
    ]
    [OOOO,L2]
  ]
\end{forest}

\end{document}